LED Drivers – The Subtle but Powerful Component Behind LED Lighting
What are LED drivers?
To completely understand what LED drivers are, it is important to first take a look at the working of LEDs, and thus, why LED drivers are needed. LED lights use a semiconductor to convert electrical current to light. The main part of an LED light is the LEDs (light emitting diodes), which are basically p-n junction diodes that emit light when they are activated by electrical current.
The thing about LED diodes is that they are low voltage devices and they require a constant current or voltage in order to operate efficiently. This means that the AC voltage that is fed into LED fixtures must be converted to the lower voltage and more constant DC voltage before it is fed into the LEDs. This is where LED drivers come in.
Basically speaking, LED drivers are the power supply unit of LED fixtures, where they convert the incoming AC power to the DC power required by the LEDs. They also play a very important role in regulating the current being fed to the LEDs, thus ensuring that they have a constant voltage or constant current.
Functions of LED drivers
What are the uses of LED drivers? Well, this is a question that most people who have just learned about LED drivers ask themselves. As already mentioned, LED drivers are the power supply unit of LED fixtures. However, they have several other functions, which make them very important when it comes to LED lighting. Below is a look at some of these functions:
- Providing low voltage to the LEDs
As already mentioned, LEDs are low voltage and low current diodes. An individual LED only requires about 1.5 to 3.5 volts, with a current of about 30mA. In a single LED fixture, all the LEDs will only use about 12 to 24 volts. Therefore, the incoming 120 – 220 volts from AC mains will be too much for the LEDs. Therefore, an LED driver plays an important role in lowering this voltage by converting the AC power to DC power.
- Maintaining a constant voltage or current for the LEDs
Current and voltage fluctuation is a common problem when it comes to AC voltage. The fluctuations are caused by a number of factors, for example, loose wiring connections, a huge draw of power by other devices, power surges due to lightning, and so on.
Since LEDs are low voltage and low current devices, any fluctuations in the mains supply that goes below their operating range will cause the LEDs to produce poor quality light, while fluctuations that go above the operating voltage/current range will degrade the LEDs. Therefore, there is a great need for maintaining a constant voltage so as to ensure that the LEDs are performing efficiently and are not damaged. This responsibility is carried out by the LED drivers by providing a regulated and constant voltage or current.
- Protecting the LEDs from overheating
LEDs work by converting electric current into light output. And since the current is an exponential form of voltage, a small change in the voltage can cause a significant (exponential) change in the current applied across an LED. Therefore, when the voltage being fed to an LED increases slightly, the result can be a huge increase in the current across the diode. As the current increases, the light output will increase (at first) but soon, the diode will start heating up.
The heat produced by the LEDs can do one of two things: 1) Completely damage the LEDs or 2) Melt the soldering that is found on the diode’s circuit. Either of these scenarios is disastrous for the LED fixtures, as it results in them not working. Fortunately, the problem is prevented by the use of LED drivers. By regulating the voltage (or current) the drivers ensure that the current being applied across the LED diodes does not exceed the maximum operating current. Therefore, the risk of the LEDs being damaged from overheating is greatly reduced.
- Dimming functions
Ever wondered how dimming works in LED fixtures? Well, you do not have to anymore. There are a number of techniques that are used to dim LEDs and the use of LED drivers is one of them. Through a technique called pulse width modulation, LED drivers are used to shortening the amount of leading current applied across a light emitting diode. The result of this is a decrease in the amount of light produced by the diode. The good thing about using a driver to dim LEDs is that it does not cause flickering, and the color change in the light produced is very minimal such that it is not noticeable.